Marsha Berger (Courant Institute, New York University). Modeling and Simulation of Asteroid-generated Tsunamis.

Four years ago, a asteroid with a 20 meter diameter exploded in the atmosphere over Chelyabinsk, Russia, causing serious damage 20 kilometers away but no deaths. We are studying the question of what would occur if such an air burst happened over the ocean. Would the blast wave generate a tsunami that could threaten coastal cities far away?

In this talk we present simulations using GeoClaw for tsunami propagation from asteroid-generated air bursts under a range of conditions and bathymetry. We also use a one dimensional model problem based on the shallow water equations that has an explicit solution in closed form to understand some of the results.

However, airburst-generated waves are qualitatively different than earthquake generated tsunamis. The shorter length scales of the airburst may make the shallow water equation model (which is a long wave approximation) inaccurate. The short time scales may make water compressibility important. We extend the model problem to the linearized Euler equations to explore the effects of dispersion and compressibility. We end with a discussion of whether or not the shallow water equations are an appropriate model for this kind of tsunami.